This is a revised application requesting funds to purchase a Leica TCS SP2 AOBS confocal microscopy system to support the research projects of a group of NIH-funded Investigators at the University of Miami School of Medicine, drawn from the Departments of Cell Biology & Anatomy, Molecular & Cellular Pharmacology, and Ophthalmology. Conventional laser scanning confocal microscopy (LSCM) is now a state-of-the-art technology for vital imaging and/or the acquisition of high-resolution optical sections from thick biological specimens. Recent advancements in this field allow real-time and multi-dimensional imaging, as well as high quality in vivo imaging. Thus this instrumentation is absolutely critical for current cutting edge research. The instrumentation requested will be dedicated primarily to a small but broad-based user group composed of molecular cell biologists and vision scientists drawn form three departments. Nine of these investigators (Key Personnel) have had extensive experience with the technology in their NIH-funded research. A number of additional investigators are new users for whom access will provide a broader range of approaches. It is estimated that the needs of this group will account for approximately 97% of instrumentation use. The remainder of the time will be made available to new investigators who join the group, and to back-up the institutional core facility, which is currently heavily overbooked. The new Leica instrument will be housed in the McKnight Analytic Imaging Core Facility. The facility will be directed and co-directed by two full-time faculty members and supervised by a dedicated technical manager who will have primary responsibility for maintaining the instrument and training new users. An advisory committee has been organized to oversee the use and maintenance of the instrument. Policies for the use and equitable sharing of the instrument, and a plan for its long-term maintenance have been established by the advisory committee. Strong institutional commitment provides ongoing support for the core facility and the instrumentation. About half of the members of the primary user group have extensive time needs for use of the instrumentation which cannot be satisfied by the single existing core facility on campus. The instrument chosen further satisfies specific technical needs that are not met by the existing instrumentation on campus. Improved access to this technology will greatly enhance the NIH-funded projects of the user group.